i m working on a project for that i need to operate a 12v relay by main AC in the range of 140V to 310V, (prefered without step down transformer) .i havtried some circuit but they break down when main reaches 270v-280v .plz solve my query 2 crop m out that problem.

 

Post your circuit or are you connecting the 12V relay directly to the mains?

Direct connection to the mains is highly discouraged as a safety issue and a potential fire hazard.

 

i m working on a project for that i need to operate a 12v relay by main AC in the range of 140V to 310V, (prefered without step down transformer) .

We do not discuss such circuits - there is no way to make them safe to use.